Functionally substituted terpolymers and tetrapolymers of alpha-olefins and process for manufacturing functional substituted copolymers

ABSTRACT

ADDITION TERPOLYMERS OF ETHYLENE WITH AN A-OLEFIN AND AN UNSATURATED, FUNCTIONALLY SUBSTITUTED MONOMER. ADDITION TETRAPOLYMERS OF ETHYLENE WITH AN A-OLEFIN HAVING 3-18 CARBON ATOMS, A NONCONJUGATED DIENE HAVING ONLY ONE POLYMERIZABLE DOUBLE BOND, AND AN UNSATURATED, FUNCTIONALLY SUBSTITUTED MONOMER. A PROCESS FOR PREPARING COPOLYMERS OF ETHYLENE WITH AN UNSATURATED FUNCTIONALLY SUBSTITUTED MONOMER, AND OPTIONALLY ALSO WITH AT LEAST ONE OF THE FOLLOWING: AN A-OLEFIN HAVING 3-18 CARBON ATOMS AND A NONCONJUGATED DIENE HAVING ONLY ONE POLYMERIZABLE DOUBLE BOND; WHEREIN THE MONOMERS ARE CONTACTED IN THE PRESENCE OF A VANADIIUM COMPOUND SOLUBLE IN HYDROCARBONS AND CHLORINATED HYDROCARBONS, IN WHICH VANADIUM IS IN THE OXIDATION STATE OF AT LEAST +3, AN ORGANOALUMINUM COMPOUND, AND AN ORGANIC COMPOUND HAVING AT LEAST ONE CARBON ATOMS SUBSTITUTED BY THREE HALOGEN ATOMS WHICH CAN BE CHLORINE OR BROMINE.

United States Patent (3 i 3,748,316 FUNC'I'IONALLY SUBSTITUTEDTERPOLYMERS AND TETRAPOLYMERS F a-OLEFINS AND PROCESS FOR MANUFACTURINGFUNCTIONAL SUBSTITUTED COPOLYMERS John Wilfred Collette, RollandShih-Ynan R0, and Fred Max Sonnenberg, Wilmington, DeL, assignors to E.I. du Pont de Nemours and Company, Wilmington, Del. No Drawing. FiledJune 2, 1969, Ser. No. 829,758 Int. Cl. C08f /40, 27/10 U.S. Cl.26080.75 2 Claims ABSTRACT OF THE DISCLOSURE Addition terpolymers ofethylene with an a-olefin and an unsaturated, functionally substitutedmonomer. Addition tetrapolymers of ethylene with an oz-OlCfiIl having3-18 carbon atoms, a nonconjugated diene having only one polymerizabledouble bond, and an unsaturated, functionally substituted monomer. Aprocess for preparing copolymers of ethylene with an unsaturatedfunctionally substituted monomer, and optionally also with at least oneof the following: an a-olefin having 3-18 carbon atoms and anonconjugated diene having only one polymerizable double bond; whereinthe monomers are contacted in the presence of a vanadium compoundsoluble in hydrocarbons and chlorinated hydrocarbons, in which vanadiumis in the oxidation state of at least +3, an organoaluminum compound,and an organic compound having at least one carbon atom substituted bythree halogen atoms which can be chlorine or bromine.

BACKGROUND OF THE INVENTION This invention relates to a newcopolymerization process and to new terpolymers and tetrapolymers havingfunctional groups which can be obtained thereby.

It is well known to copolymerize certain ole'finic and vinyl monomers inthe presence of free-radical generating initiators. Some olefinicmonomers, such as propylene, isobutylene, and butene either cannot bepolymerized at all in the persence of free-radical initiators or can bepolymerized only to low molecular weight polymers. Polymerization ofdiolefins or divinyl compounds by a free radical process leads to highlycrosslinked polymers which are of limited practical value.

Coordination catalysts, which allow a much better control of thepolymerization process, often are not suitable for use with monomershaving functional groups containing elements other than carbon andhydrogen. Usually, coordination catalysts tend to complex with polarfunctional groups and such complexed catalysts either become completelydeactivated or decay at afast rate.

Copolymers of olefinic monomers with several monomers containingfunctional groups have been reported. Terpolymers of ethylene withpropylene and certain unsaturated acid amides, nitriles, anhydrides, andesters have also recently been described in US. Pat. 3,278,495. However,neither terpolymers of ethylene and ot-olefins with monomers containingother functional groups nor tetrapolymers of ethylene with oz-OlfifiBS,dienes and functional monomers are known.

SUMMARY OF THE INVENTION Accordingly, it has now been discovered thatnovel elastomeric ethylene random terpolymers with a-olefins having 3-18carbon atoms and unsaturated functional monomers and of tetrapolymerswith nonconjugated dienes having only one polymerizable double bond canbe readily made using a coordination catalyst based on a vanadiumcompound, in which the vanadium is in the e, CC

oxidation state of +3 or higher. Random distribution of the monomerunits in a terpolymer or tetrapolymer molecule is often useful for goodelastic properties of the material. An aluminum aryl or alkyl or anarylor alkylaluminum chloride or bromide also is present. When thefunctional groups of the monomer contain either oxygen or nitrogen, themolar concentration of the organoaluminum compound is at least equal tothat of the functional monomer. Reduced vanadium is regenerated by anoxidizing agent which is preferably an organic compound having at leastone carbon atom substituted by three halogen atoms selected fromchlorine and bromine. The copolymerization is run in solution in anorganic solvent.

The following monomers having functional groups can be copolymerizedwith ethylene and optionally also with an a-olefin, a nonconjugateddiene, or both, by the process of the present invention:

( 1) Compounds of the Formula I CH ==CH-(CH X m1=2-20 where X can be oneof the following groups: OR, --NR;,

--F, -Br, or -Cl and R can be alkyl, aryl, or cycloalkyl containing 1-18carbon atoms, or hydrogen;

(2) Compounds of Formula II CH =CH-(CH ),,Y n=020 where Y can be one ofthe following groups:

where R can be alkyl, aryl or cycloalkyl, containing 1-18 carbon atoms,or hydrogen; R can be either R or OR.

(3) Compounds of the Formula III (OHzh-Z, n=0-20 where Z can be either X[as defined in (1) above] or Y [as defined in (2) above]; and

(4) Compounds of the Formula IV T (IV) where T can be hydrogen, OH, C -Calkyl, C C alkoxy, or a halogen.

CH CH=CH 2 OH (VII) 1) (VIII) CH2=CH(CH2)mNH3 (IX) cHg=CH -(GH3) sO2C1(XI) C H2)u-s 1 Cl (XII) ii CHg=CH'-'(CH2) m-CR (XIII) ll 2) n R (XIV)where R, R m and n have the same meaning as in Formulas IIV, above;these functional monomers all are derived from, and are special casesof, the broader classes of monomers represented by Formulas I-III.

DETAILED DESCRIPTION OF THE INVENTION Copolymerization of ethylene witha functionally substituted monomeroptionally also with an a-olefin, anonconjugated diene, or both-can be run either batchwise orcontinuously, at either atmospheric or superatmospheric pressure. Asolvent usually is employed, although it is not absolutely necessary.Good solvents are aliphatic hydrocarbons such as pentane, hexane,heptane, octane, and isooctanes; cycloaliphatic hydrocarbons such ascyclopentane, cyclohexane, cycloheptane, and. cyclooctane; andhalogenated aliphatic hydrocarbons, for example, perchloroethylene,carbon tetrachloride, methylene chloride, and chloroform.

The reaction catalyst is composed of the following constituents (a) Avanadium compound in which vanadium is in an oxidation state of +3 orhigher; for example, VCl VOCl vanadium tris(acetylacetonate); vanadiumhalide complexes with ethers, amines or phosphines (for examplecomplexes of V01 with dioxane, pyridine or triphenylphosphine); andesters and haloesters of vanadic acids (such as diethoxyvanadiumdichloride, triethyl vanadate, or diethoxyvanadi'um oxychloride). Thevanadium compound should be soluble in hydrocarbons and chlorinatedhydrocarbons.

(b) An organoaluminum compound of the structure (R2)3A1: 2)3 2 a, 2I2 0T2) 2, Where 2 is aryl or a C -C alkyl, such as methyl, ethyl, propyl,isopropyl, butyl, isobutyl, pentyl, or hexyl; and L is chlorine orbromine.

Representative organoaluminum compounds include: triisobutylaluminum,diisobutylaluminum monochloride, triethylaluminum, diethylaluminumchloride, ethylaluminum sesquichloride, diethylaluminum bromide,ethylaluminum dichloride, propylaluminum dibromide, andtriphenylaluminum.

(c) A halogenated compound of the general formula DCL where L has thesame meaning as above, while D can be hydrogen, chlorine, bromine,alkyl, aryl, haloalkyl, haloaryl, carboxyl, alkoxycarbonyl,aryloxycarbonyl, alkylcarbonyl, arylcarbonyl, alkoxy, aryloxy,haloalkoxycarbonyl, haloaryloxycarbonyl, haloalkylcarbonyl,haloarylcarbonyl, haloalkoxy, haloaryloxy, or the group where A, A and Aeach can independently be a halogen, alkyl, haloalkyl, aryl, haloaryl;and A also can be hydrogen.

Representative halogenated compounds are, for example, chloroform,bromoform, carbon tetrachloride, u,a, a-trichlorotoluene,u,u,a-tribromotol uene, trichloroacetic acid, tribromoacetic acid,perchloropropylene, hexachloroacetone, ethyl trichloroacetate and ethyltribromoacetate.

Normally, at least two moles of organoaluminum compound are present foreach mole of vanadium compound. However, the preferred ratio is about10:1 or more. Organoaluminum compounds required in this process aredecomposed in the presence of monomers having active hydrogen atoms,such as carboxylic acids or alcohols. Furthermore, they are complexedand deactivated by oxygenand nitrogen-containing polar groups. It is,therefore, advantageous to have in the mixture a sufiicient amount ofthe organoalurninum compound to at least compensate for itsdecomposition or deactivation. .An excess of the organoaluminum compoundis not harmful, and molar ratios of aluminum to vanadium compounds ashigh as 200:1 or more can be present in the catalyst.

The halogenated compound DCL acts as a catalyst reactivator and it canbe present in a large excess, for instance, in an amount of 10 moles permole of vanadium compound. However, the amount of the reactivator shouldbe kept within the range of about 0.01-1 mole per mole of theorganoaluminum compound present in solution. Below the lower limit thereactivation of the vanadium catalyst is not quite efiicient, whileabove the upper limit there is a risk that polymerization may proceed byan undesirable ionic mechanism. The vanadium compound is present incatalytic amounts only, for example, 0.000050.005 mole per mole of totalunsaturated monomers.

The practical concentration ranges of the essential compounds in thepresent copolymerization process are tabulated below:

gen-containing groups. Catalyst reactivator. 0. 00001-0. 1 Must be atleast equal to vanadium catalyst concentration.

Polymerization is run in the absence of moisture in an inert atmosphere,for example in dry nitrogen, and at a temperature of -20 to C. Thepreferred temperature range is 0-65 C. Below 0 C. it is bothinconvenient and expensive to remove heat evolved during thepolymerization. Above about 65 C. the molecular Weight of the copolymerproduct can fall below a desirable value. It is usually convenient tocarry out the copolymeriz-ation at atmospheric pressure, but reasons ofeconomy of time or equipment may sometimes favor closed systempolymerizations at autogenous pressures or higher. It is usuallypossible, for example, to increase the monomer concentration in solutionin a closed system; and a smaller reactor, therefore, can be used thanat atmospheric pressure. .When polymerization is run in a closed system,pressures up to about 10,000 p.s.i.g. can be used, but it is notpractical to exceed a pressure of about 5000 p.s.i.g.

Although the process of the present invention is susceptible to changesand variations without departing from the spirit of the inventiveconcept, a typical batchwise atmospheric pressure copolymerizationinvolves the following steps: ethylene, and optionally a comonomeraolefin, are dissolved in an appropriate solvent suchasperchloroethylene, and an alkylaluminum compound is added. This isfollowed by addition of an unsaturated functional monomer, optionally adiene, then a catalyst reactivator and finally, a vanadium compound. Thesolution is stirred for about 30 minutes, while ethylene and any gaseousmonomers are continuously swept through it. The polymerization isstopped by destroying the catalyst system, for example by adding analcohol. The reaction time in some cases may be as short as one minute,while in other cases a period of two hours or more may be required toobtain satisfactory yields of the copolymer.

The process of the present invention can also be operated in acontinuous manner. It often is desirable in such a case to increase thereaction pressure in order to reduce the residence time. The reactoreffluent is continuously removed.

The product copolymer can be isolated by several known techniques, butit is preferred to precipitate it with a nonsolvent such as methanol andto Wash it. The functional groups of a crude copolymer often retainresidual aluminum compounds, and, since a copolymer containing residualaluminum is unsuitable for most applications, removal of any aluminumcompounds present is advisable. Where a copolymer is precipitated fromsolution with an alcohol, it usually is sufiiciently free from aluminum,but when the copolymer contains carboxylic groups, it may be necessaryto remove the last traces of aluminum compounds, for example by atreatment with trifiuoroacetic acid. When other isolation methods areused, for example evaporation or phase decantation, it is practical toremove residual aluminum compounds by washing the copolymer solutionwith a large excess of a dilute acid, such as sulfuric, hydrochloric, oracetic acid and to remove the acid by washing with water.

Alpha-olefins which can be used as comonomers in the process of thepresent invention can be either straightchain or branched.Representative a-olefins include propylene, butene, pentene, hexene,heptene, decene and octadecene. Propylene is the preferred a-olefin.Nonconjugated dienes which have only one polymerizable double bond canbe present in addition to u-olefin comonomers. These include1,4-hexadiene, S-methylene-Z-norbornene, 5 (2- butenyl)-2-norbornene,dicyclopentadiene, 5-ethylidene-2- norbornene, 11-ethyl-1,11tridecadiene, and 1,5 -heptadiene.

The unsaturated functional comonomers can have active hydrogen atoms,provided at least a stoichiometric amount of aluminum alkyl oralkylaluminum halide also is present to prevent catalyst deactivation.Generally, the farther is the functional group removed from the doublebond, the easier and more complete is the copolymerization of thefunctional comonomer. Typical compounds of the group defined by FormulaI include 4-pentene-1-ol, 5- hexene-l-ol, -undecene-1-ol, 4-pentenylmethyl ether, 5- hexenyl methyl ether, S-hexenyl diethylamine,6-heptenyl methylethylamine, 4-pentenyl trifluoroacetate, 6- heptenyltrifluoroacetate, 4-pentenyl metyl ketone, S-hexenyl methyl ketone,6-heptenyl vinyl ketone, IO-undecenyl chloride, 6-heptenyl chloride and4-pentenyl acetate. When the unsaturated functional monomer is a memberof the group defined by Formula II, it can be, for example, one of thefollowing compounds: acrylic acid, methacrylic acid, vinylacetic acid,10-undecenoic acid, allylacetic acid, methyl acrylate, ethyl acrylate,propyl acrylate, methyl methacrylate, ethyl methacrylate, butylIO-undecenate, ethyl vinylacetate, propyl vinylacetate, methylallylacetate, butyl allylacetate, N,N-dimethylacrylamide, acrylamide,N,N- diethyl vinylacetamide, acrylonitrile, methacrylonitrile, 2-allylphenol, 2-methoxy-4-allylphenol, allylsulfonyl chloride andS-norbornene-2-sulfonyl choride. The unsaturated functional monomer canalso be a Z-norbornene derivative, as shown in Formula III. It thus canbe, for example, 2-norbornene-5-acetic acid, 2-norbornene 5propionamide, 2-norbornene-5-methanol, 2 norbornene 5- ethyl methylketone, 2-norbornene-5-acetonitrile, or ethyl 2-norbornene-5-acetate.Monomers having structures represented by Formula IV include, forexample, 8-phenoxy- 1,6-octadiene; 9-(2-hydroxy)phenoxy 1,6 octadiene;8- (4'-chloro)phenoxy1,6-octadiene; 8-(4I-methyl)phenoxy- 1,6-octadiene;and 8-(4-methoxy)phenoxy 1,6 octadiene. All these compounds are known inthe art.

Although the proportions of comonomers can be varied, it is preferred tomaintain the amount of a-olefin (when present) at such a level that itwill constitute 5-75 weight percent of the product copolymer, preferablyabout 20-60 weight percent. Functional unsaturated monomer is present insuch an amount that it will constitute 0.1-10 mole percent of theproduct. When a nonconjugated diene is used in addition to ethylene andoptionally a-olefin, it generally is employed at a level which will give0.1-5 mole percent diene component in the final copolymer. The amount ofethylene can be varied within rather broad limits, so long as the aboveproportions are maintained.

The novel copolymers of the present invention have desirable physicaland chemical properties which make them useful for a number ofapplications. Thus, for example, the solubility and dispersibility of anolefinic polymer are modified by the presence of functional groups. Acopolymer having functional groups is more compatible with polarsolvents than a hydrocarbon polymer. Carboxyl groups impart goodabrasion resistance, allow formation of stable latices, and improveadhesion. Hydroxyl groups provide active sites which allow crosslinkingand/ or chain extension, for instance with polyisocyanates. Otherfunctional groups, such as amino groups, improve dyeability of acopolymer. These new terpolymers and tetrapolymers are useful inadhesives, especially when a nonpolar material must be bonded to a polarsubstrate (e.g., when bonding elastomer stocks to tire cords).

This invention will be better understood if reference is made to thefollowing examples of some specific embodiments thereof, where allparts, proportions and percentages are by weight, unless otherwiseindicated.

EXAMPLES General copolymerization procedure for ethylene/propylene/functional monomer terpolymers Batch polymerizations arecarried out at atmospheric pressure in an oven-dried 3-necked 1000-ml.flask equipped with a serum cap, a stirrer and a thermometer. The flaskis swept with nitrogen and filled to the 500 ml. mark withperchloroethylene at about 15 C. Ethylene and propylene are first sweptthrough the solvent for 10 minutes at the rate of 1 l./rninute and 2l./minute, respectively.

In a typical experiment, while ethylene and propylene are continuouslyintroduced at the above rates, 5 ml. of a 4 M solution ofdiethylaluminum chloride (0.02 mole) in perchloroethylene is addedthrough the serum cap, followed, in turn, by a solution of 0.01 mole ofunsaturated functional monomer in 15 ml. of perchloroethylene and 1 ml.of a 1.0 M solution of hexachloropropylene (0.001 mole) inperchloroethylene. The temperature is adjusted to 20 C. and 1 ml. of a0.1 M solution of VCL, perchloroethylene (0.001 mole) is added.

The temperature is maintained at 20-30 C., cooling the flask in an icebath, as necessary. After 30* minutes, from addition of VClpolymerization is terminated by the addition of 3 ml. of isopropylalcohol.

Workup involves removing a 100-ml. sample and adding it dropwise to 500ml. of methanol in a blender to precipitate the polymer; the liquid issubsequently decanted. Another 500 ml. of methanol is used to wash thepolymer. The isolated polymer is dried at C. for at least 3 hours in avacuum oven.

When the copolymer contains carboxylic groups, the copolymer solutioncan be treated with trifluoroacetic acid (TFAA) to remove last traces ofthe catalyst. The solution (250 ml.) is mixed with 30 ml. of TFAA andallowed to stand overnight. The solid catalyst residues are filtered;

Adhesion testing of functional tetrapolymers Hard kaolin clay: Suprexclay, (I. M. Huber Corp; New York) is an air-floated hard kaolin typecharacterized by the following equivalent analysis: 44-46% silica,

and the filtrate is treated with 10 ml of TFA-A and 7 .alumina P. 14%filtered immediately The filtrate is concentrated in a i z gg (110x151;w lgmtlon loss i io E y weig t. 13 am ysis oes not mean at e {giggi g 2gfigi fi jigg jglgl i gig i g ggi clay necessarily contains silica oralumina. The moisture concentrated to about 100 ml. and added dropwiseto 500 gg ssz f g a f 2: gg f gg gg g gag??? m1. of vi orousl stirredacetone. The reci itated ol mer is decant ed and dried in a vacuumIZWCIIP for at le st 3 a 325-meSh Sc-reen f 9 9 Welght and the hours atC following particle size distribution (by weight):

The results of experiments 1-10 run both with and 10, 1 15%; 4, withouthexachloropropylene (HCP) (as catalyst re- 15 1, 911%; 109%; M,activator) are presented below in Table II.

TABLE II Adhesion of ethylene/propylene/1,4-hexadiene/funcmm of c 01 atfrom tional monomer tetrapolyiners towards Suprex Clay is de- Y 0p m Ex500 m1. of solution termined m the following manner: Monomer with HOPWithout 0 The tetrapolymer grams) and Suprex clay (24 1 M b e e 14 o 04grams) are compounded on a rubber mill. The com- 2333; ztgflugomtghggthglr: 3 130 p ded polymer is loaded cold into a 1" x s" slab mold 3 V2 0gbgme5n %o be we g 42 0 1 5 and heated at 100 C. for 3 minutes. Thespecimen is g f g fi g ggfig" 1 allowed to cool, unloaded, and thetensile strength at g g l l lgg en l gig {-2 break T is determined at 25C. on an Instron machine i ggg t 1830 3 in accordance with ASTM MetthodD-412-66. g i g gg g gi-g fi%i g gig g The results are presented inTable IV, below: 10:: 2-hydroxymethyl-fi-norbornne:II: 37.5 5:4 TABLE IV1 Control experiments, outside the son 0 of this invention. 30 w 2 Inthis experiment, 0.02 mole of ethy luminum dichloride is used. U tDammit f nsa upropy one visc., General copolyinerization procedure forethylene/ 3%: Funetionalmonomer ggg 33 E 23;propylene/1,4-hexadiene/tunctional tetrapolymers 16.--- d vinylpyridine0.75 25.3 0. 98 510 The procedure described above for the preparation of35 18 2-hydgoxymethyl-5- 0.17 33.0 1. 210 terpolymers is used withslight modifications. Ethylene Com M0 424 217 and propylene areintroduced into perchloroethylene at trol o C' at the ate P The amountof dlethyl 1 As asolution of 0.1 g. of tetrapplymer in 100 ml. ofperchloroethylene. aluminum chloride is increased to 25 ml. (0.10 mole)and ietr ago i y g r llladeelgyt lgvtibggtlg glpg E-saturati n andcontain In e n 0 the amount of funcuonal monomer to mole- L4 40 mg th efollowing mgi i mer unit compositio n: ethylene 52.1; propylene, hexadene, 12 m1, (0,10 mole) 15 added through the 44.0;1,4-hexadiene,3.9.Itismadeln perohloroethylene inthe presence of septum. The amount of 0.1 Mvci is 3 ml. 0.0003 mole), g ggggg ggge g sg 5 g; g g gg ffifiii i gjfgsgg ggggg and 3 ml. of 1.0 M (0.003 mole) hexachloropropylene is 40.added at 5 C. The tetrapolymer is recovered by pre- These results showthat even the unvulcanized tetracipitation with 2 liters of methanol andwashed with 2 45 polymers give tough and strong clay-filledcompositions. liters of methanol. The copolymer is vacuum oven-driedTension at break is indicative both of adhesion of the overnight at C.The results are presented in Table III. tetrapolymer to the clay and ofinternal cohesion of the TABLE III Percent incorporation Copolymer bywt. of Unsatura- Example yield, monomer in tion, number Functionalmonomer grams eopolymer moles/kg.

11 CHFCH(CHZ)4OH 40.1 2.1 0.69

CH -CH=CHa CH2C 02H 14 CH2=CH-(CH2)5COOH 31.8 0.75

Q-CH NHf N 0 CH=CH2 17 GH2=CH-CH2S0tCl 46.1 0.2 0.68

1 Not determined-Strong 0:0 band evident in IR spectrum: 1 0.15 mole ofdiethylalumlnum chloride used.

tetrapolymer itself. Comparison with a control terpolymer not containingfunctional groups shows the low T value obtained for such a terpolymer.

We claim:

1. An addition copolymer of (1) etthylene, (2) propylene, (3)1,4-hexadiene, and (4) an unsaturated functional monomer, saidfunctional monomer being 2-hydroXy-5- norbornene.

2. An addition copolymer of (1) ethylene, (2) propylene, (3)1,4-hexadiene, and (4) an unsaturated functional monomer, saidfunctional monomer being 2-i1ydroxymethyl-S-norbornene.

References Cited UNITED STATES PATENTS 3,070,577 12/1962 Stogryn 260'623,203,940 8/1965 Long 26088.2R

1 0 3,250,754 5/1966 Stewart 260-80.8 3,476,726 11/1969 Giannini 26089.7N 3,310,537 3/1967 Natta 260-795 3,328,362 6/1967 Roberts 26079.33,345,419 10/1967 Tinsley 260--6l7 3,380,952 4/1968 Cluff 26033.83,481,909 12/ 1969 Di Pietro 26080.78

JOSEPH L. SCHOFER, Primary Examiner 10 C. A. HENDERSON, JR., AssistantExaminer US. Cl. X.R.

117-122; 26041.5 A, 47 UA, 63 BB, 67 UA, 775 CR, 79.3 MU, 80.3 N, 80.6,80.72, 80.73, 70.75, 80.76, 80.78, 80.80, 80.81

